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loading of an ammeter in a circuit decreases the flow of current,so it has to be calculated to reduce expected errors in the operations
It depends. If it's an inductive ammeter (the kind that clamps around a wire), it won't work at all. If it is the type of ammeter that is actually placed in the circuit, it will work but it won't be accurate.CommentActually, modern 'clamp on' ammeters WILL measure d.c. currents. It uses the Hall Effect to measure the current.
An ammeter has a finite resistance which is inserted in series with the rest of the circuit, increasing the total resistance and decreasing the current. A good ammeter has a very low resistance, so it shouldn't affect the circuit noticeably.
The ammeter does affect the flow of current in a circuit, however, the resistance of the ammeter is so small in comparison to the circuit that the effect is negligible. It is connected in series.
Since internal resistance of the ameter will increases the resistance of the circuit. Thus decreasing the current giving an errorenous reading.
The voltmeter has an internal resistance, which should be as high as possible. As this resistance draws current from the circuit under test, it will affect circuit operation. This is more pronounced in a high impedance circuit because the current drawn flows through higher resistances.
The effect the multimeter might have on the circuit when inserted to measure the current is to increase the circuit resistance and decrease the available voltage to the circuit. This is because the multimeter in amps or milliamps mode does have a small resistance which is not zero, so by Ohm's law, there is a voltage drop across the multimeter; small, but not zero. Usually this effect is small. One way to compensate is to start by measuring voltage, and then inserting a separate ammeter and adjusting the power supply to match the original voltage. Of course, the voltmeter must be downstream of the ammeter.
ammeter connect in series in circuit to measure the current, if the Ammeter have a high resistance it would effect the voltage value because there will be a drop voltage over the internal resistance of the Ammeter, so we desgin the ammeters with very low resistance...
You don't. ...unless you want to directly measure the current in a circuit branch. That's the purpose of an ammeter. You can also use a volt meter if you know the resistance of a resistor in that branch to determine current (assuming DC circuit here) - current = voltage / resistance. This may be more useful for circuitry that is on a breadboard, since inserting an ammeter may not be practical.
The readings on an ammeter indicate the current being drawn by a load in a circuit. This load is basically a resistance to current flow. The higher the resistance, the lower the current. The supply voltage has a direct effect on current flow. The higher the voltage applied, the higher the current will be. So the readings will vary on the ammeter according to fluctuations in load and or resistance of the circuit and the applied voltage.
An ammeter is placed in series with a circuit in order to measure the current. If it has any appreciable resistance, inserting the ammeter will increase the normal resistance of the circuit and reduce the value of the current flowing through it. The ammeter will, therefore, give an inaccurate reading (under-read). So the ammeter must have a very low resistance so that it has the minimum effect on the normal resistance of the circuit being tested. Ideally, the ammeter should have zero resistance but, of course, this is impossible.
That depends on the quality (price) of the meter. Ideally it should have no effect.